Disclosed embodiments herein relate generally to micro electro-mechanical systems (MEMS) assemblies, and, more specifically, to methods for lubricating internal MEMS assembly components during the manufacturing process using an opening in the MEMS assembly package.
Optoelectronic devices have continued to gain popularity with today""s top manufacturers. Specifically, micro electro-mechanical devices, such as actuators, motors, sensors, and micro electro-mechanical systems (MEMS), such as spatial light modulators (SLMs), are some of the few types of optoelectronic devices gaining in use. Such packaged SLMs and other types of MEMS devices are employable in xe2x80x9cdigital micro-mirror devicexe2x80x9d (DMD) technology, of the type designed and used by Texas Instruments of Dallas, Tex.
Such DMD MEMS assemblies include arrays of electronically addressable mirror elements (or xe2x80x9cpixelsxe2x80x9d), which are selectively movable or deformable. Each mirror element is movable in response to an electrical input to an integrated addressing circuit formed monolithically with the addressable mirror elements in a common substrate. Such MEMS assemblies modulate incident light in a spatial pattern, pursuant to an electrical or other input, in phase, intensity, polarization or direction. The incident light is modulated by reflection from each mirror element.
Unfortunately, defects may be caused by contamination of the MEMS mirror array during various stages of the manufacturing process. For example, at certain points, the MEMS array may be stripped of any protective layer, exposing the MEMS array to contaminates before it is sealed within the MEMS assembly. More particularly, contaminants, often in the form of debris particles, may contaminate the mirror array during the wafer saw process, array mounting stage, wire-bonding processes, and even the during the final assembly stage for the MEMS assembly. Such contamination may detrimentally affect the function of the mirror, and as the number of defects increases, so too does the overall manufacturing costs due to decreased wafer yield.
To address the above-discussed deficiencies of the prior art, the present invention provides, in one aspect, a method of manufacturing a MEMS assembly. In one embodiment, the method includes mounting a MEMS device, such as a MEMS mirror array, on an assembly substrate. The method further includes coupling an assembly lid to the assembly substrate and over the MEMS device to create an interior of the MEMS assembly housing the MEMS device, whereby the coupling maintains an opening to the interior of the MEMS assembly. Furthermore, the method includes lubricating/passivating the MEMS device through the opening.
In another aspect, the present invention provides a MEMS assembly constructed according to a process of the present invention. In one embodiment, the MEMS assembly is constructed by mounting a MEMS device, such as a MEMS mirror array, on an assembly substrate. The MEMS assembly is further constructed by coupling an assembly lid to the assembly substrate and over the MEMS device to create an interior of the MEMS assembly housing the MEMS device, whereby the coupling maintains an opening to the interior of the MEMS assembly. Furthermore, the MEMS assembly is constructed by lubricating/passivating the MEMS device through the opening.